A facsimile apparatus with an audio response function has been used heretofore. This has the following design. When a ring signal is inputted from a telephone line, the telephone line is automatically closed and a response message (referred to as an OGM hereinafter) is transmitted. Then, it changes to the operation of receiving facsimile information. In another case, after an OGM is transmitted, it changes to the operation of recording a speech if the signal inputted from the telephone line is the speech (referred to as the ICM hereinafter). It changes to the facsimile operation if the signal inputted from the telephone line is a facsimile communication start signal (referred to as a CNG signal hereinafter) or is soundless.
A prior art facsimile apparatus with an audio response function, which is such as mentioned above, will be described hereinafter with reference to drawings.
FIG. 7 is a block diagram showing the structure of a prior art facsimile apparatus with an audio response function. FIG. 8 is a flowchart showing its operation. In FIG. 7, 1 is a telephone line, and 2 is an interface circuit connected to the telephone line 1. The numeral 3 is a ring signal detecting circuit for detecting a ring signal coming from the telephone line 1. The numeral 4 is an OGM transmitting circuit 5 such as a tape recorder, 5 is an ICM recording circuit such as a tape recorder, 6 is a facsimile communication circuit, 7 is a speech signal detecting circuit, and 8 is a change circuit. The numeral 9 is a CNG signal detecting circuit for detecting a CNG signal coming from the telephone line 1, and 10 is a control means composed of a microcomputer. The numeral 11 is a timer provided in the control means 10.
Hereinafter, a description will be given of the operation of the facsimile apparatus with the audio response function which is designed as above.
When a ring signal is inputted from the telephone line 1, the ring signal detecting circuit detects this (a step 1) and outputs it to the control means 10. The control means 10 controls the interface circuit 2, closing the telephone line 1 (a step 2). Next, the control means 10 controls the OGM transmitting circuit 4, outputting an OGM to the telephone line 1 (a step 3). When the control means 10 detects an end of the transmission of the OGM (a step 4), it controls the ICM recording circuit 5 to record the signal inputted from the telephone line 1 (a step 5) and operates the timer 11 (a step 6). With respect to the end of the transmission of the OGM, in the case where a medium into which the OGM is recorded is a tape, a beep sound is recorded into a position of the end of the recording of the OGM, and the OGM is ended when the beep sound is detected. In the case where a medium is an IC, there are known methods such as a method in which an address occurring at an end of the recording of the OGM is detected, and the OGM is ended at this address position. A description of the details thereof will be omitted.
Simultaneously with the recording of the ICM, the control means 10 enables the speech signal detecting circuit 7 and the CNG signal detecting circuit 9 to monitor a signal inputted from the telephone line. In the case where the signal inputted from the telephone line 1 is a speech (a step 7), it keeps the operation of recording the ICM as it is. In the case where the signal inputted from the telephone line is a CNG signal (a step 9), the control means 10 changes the change circuit 8 to the facsimile communication circuit 6 (a step 10). In the case where both the above-mentioned signals are not detected, a decision is made as to whether or not the count of the timer 11 is completed (a step 11). When it is not completed, the return to the step 7 occurs. When it is completed, the control means 10 changes the change circuit 8 to the facsimile communication circuit 6 (the step 10).
However, in a structure such as mentioned above, in the case where a CNG signal is inputted from a calling side during the transmission of an OGM, if a signal similar to the CNG signal is accidentally recorded in the OGM, there is a chance that a signal which results from a return of a self-outputted OGM of the OGM via the telephone line is erroneously detected as a CNG signal. Therefore, during the transmission of the OGM, the detection of the CNG signal is not executed. Accordingly, there is a problem that facsimile communication can not be done during the transmission of the OGM. Thus, in the case where the length of the OGM is supposed to be one minute, there is a problem that facsimile communication is not done during one minute after a call incoming.
In the case of a facsimile apparatus, standards prescribe that a calling side should open a telephone line if a time from the moment of the closing of the telephone line by the calling side to the moment of the reception of a signal of a receiving side is equal to or longer than a given time. Thus, there is a problem that facsimile communication can not be done if the OGM is long.